Toric-tool protractor



J. H. PEARSON.

TORIC TOOL PROTRACTOR.

APPLICATION FILED NOV. 26. 1918.

1,356,656. Patented Oct.v 26, 1920.

I N V EN TOR. Jaw/1 HAerEr P154250 A TTORN [1' Y5 UNiTE sI' tare-NT cr n es.

JoHN HARVEY rEAasoN, or INDIANAPOLIS, INDIANA, AssIGNon TO ONEP IECEQ BIFOCAL LENS COMPANY, or INDIANAPOLIS, INDIANA, A coaroRA'rIo 1 TORIC-TOOL PROTRACTOR.

To all whom it may concern:

Be it knownthat I, JOHN HA vEY PnAn- SON, a citizen of the-United States, and a resident of Indianapolis, county of- Marion, and-State of Indiana, have lnvented a certain new and useful ,Toric-Tool Protractor;

and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompany ng drawings, in which like lettersrefer tolike parts. p The object of this invention is to :eflect a proper setting or adjustment of tone tools for grinding cylinders and compound lenses. It is necessary for accurate and satisfactory work that the toric tools he set at the axes called for in the prescription.

The device is for the accurate mountingof toric tools, preferably two tools, in a tool holder at the proper axes wlth reference to the tool'holder, and after the tools are set in the tool holder,.it is readily removable from the. protractor and placed in a machine for grinding lenses with said tools. The

protractor is a separate device andindepend ent of the grinding machlne; and its only function is for the setting and ad ustment.

of the toric tools in the tool holder.

The chief feature of the invention consists in mounting the tool holder in connection with a device having indicated on it a protractor for giving axes and mounting the toric tool in such holder adjacent said protractor adjusted so that the axls marked on said tool will register with the proper axis called for by the prescription, as ind1cated on the protractor, and then clamping the tone tool tightly in saidholder so that when the holder is put in place in the mach ne for grinding the lenses, the toric tool is set with absolute accuracy for giving to the lens the proper axis.

The full nature of the invention willbe understood from ,the accompanying draw-- ings and the following description and claims:

In the drawings, Figure 1 is a plan view of the machine. Fig. 2 is a front elevation thereof. Fig. 3 is a vertical transverse section on the line 3-3 of Fig. 2. F1g. 4 is a similar section on the line 4-4 of Fig. 2.

The protractor device consists of a frame having a base 10 whereby. the device can be readily set on a table or stand and at 'the scale and when the toric tool is 26, 1918.. Serial No. 264,190.-

rear side of-said base a. wall or plate 11 ex- 7 tends vertically for the entire. length of the base 10 and is centrally reinforced by a vertical rib 12. The rib 12 is widened at its upper end. to form a widened and forwardly extending lug 13 from which a threaded clamping bolt 14 projects forwardly. each side of the plate 11 there is also an Specification of Letters Patent. Paten td 0 1;, 26,1920

Near

otheriforwardly extending lug 15, as seen in Fig.4, from which a headless pin 16 projects forwardly, the protruding portion thereof'not being threaded so that these two lateral pins serve only as stop. or support ing plns. On the rear of the upright frame or plate 11 there is a vertically extending guide projection 17, see Fig. 3, and from the upper end of said guide there is a threaded bolt'18 projecting. rearwardly This bolt is in the .samevertical plane as the bolt 14, but is on a little higher level than sald bolt 14, as seenin Fig. 3.

A top scale plate 20 made of relativelythin metalis secured by screws 21 along its rear edge to a vertical supporting plate 22, see Flgs. 3 and 4, which has a central vertical slot 23 for the bolt 18 to extend through and at its center said plate 22 hasa 'verti- I cally disposed thickened. portion 24. A

washer 25 and nut 26' on bolt 18 enables the j,

plate'22 tobe' vertically adjusted as desired. .The device which 'is shownherein is for adjusting two toric tools at atime and,v therefore, the scale plate 20 has two semicircular recesses-30 in its 'forward side of the proper size to receive the toric tool 31.-

Around the margin of said semi-circular recess 30there is a. protractor scale 32 indicating 180. degrees and having numerals in-- dicating said degrees.

The toric tools are made in the usual form and have central downwardly extending shanks 35 adapted to be. inserted in a vertical hole 36 in a tool holder 37. The tool holder herein shown, as seen in Fig. 3, is a bar with two of the vertical holes 36,

one near each end so that said-holder car ries two tools, one near each end,-and the holder has near each end alset screw 38 for securing the'tools in said holder when v properly adjusted. At the center of the holder 37 there is avertical slot 40 ;with a rounded upper'surface so that it fits astride the bolt 14 extending centrally andforwardly from the main frame. On said bolt '14 there is a washer 41 and a nut 42 for clamping the holder in positionin the device so that the toric tools will fit in the recesses 30 of the protractor or scale plate 20..

The scale plate is Vertically adjusted and set so that it will be substantially flush with the upper edge of the tools when the tools are mounted in the manner described. The tool holder at each end rests directly upon the pin 16 so that there is nv opportunity for the tool holder to be inaccurately placed ordisplaced. With this arrangement it is very easy to mount the tool holders and the tools in the machine with absolute accuracy.

Each tool has an axis mark 50' on its margin and that mark has been made with particular reference to the surface which hasibeen ground on the tool and also with the lenses to be ground by the tool. Such a lens 51 is" indicatedby dotted lines in" F ig. 1, and said axis mark 50 indicates not only the. axis lens;

The tools are mounted loosely in the holder before they are set and then they are turned and are adjusted a ngularly until the axis mark 50 registers with the proper scalemark and degree called for by the prescription for theaxisof the-lens. Thus if .of the tool but also of the the prescription calls for an axis of zero or 180 degrees, the tool will be adjusted, as shown at the left-hand end of Fig.1. If

the tool for the other lens calls for an axis of .50 degrees, it is set with the axis mark at 50 degrees. Then the set screws 38 are tightened until the tools are tightly secured in the holder." The holder isnow ready to be removed by releasing the nut 42 and washer 4:1. and taken from this apparatus and mounted in the grinding machine which may be of any usual type. 1 Thus the relation of the tool to the holder is absolutely and accurately fixed by this protractor so that the axis of the lens will be accurately produced. 7 The, invention clalmed 1s 2' 1. A protractor for the mounting oftoric tools in tool holders, including a frame in connection with which the toric tool holder is removably mounted, a plate having a graduated surface curved so as to be in close proximity with a portionof the circular periphery of the surfacing part ofa tool, whereby the tool can be adjusted in its holder at the proper axis, and means for adjusting the position of said plate on the frame to accommodate it to different tools and holders.

3. A protractor for the mounting oftoric tools in tool holders, including a frame in connection with which a toric tool holder is removably mounted which'is adapted to hold simultaneously a plurality of' toric' tools, and a plate hav ng a correspondingplurality of graduated and curved surfaces adapted to conform to the curvatures of the toric toolsand be located near-their peripheries.

- e. A protractor for-the mounting of toric tools in tool holders, including a frame, a

plate mounted thereon with two graduated surfaces, means projecting from said frame substantially midwaybetween said graduated surfaces on which a holder for a pair of'toric tools is adapted to be removably secured, and means on saidframe for en gaging and holding the ends of said tool holder in position.

5. A protrac'tor for the mounting of toric.

tools in tool holders, including a frame, a

plate mounted thereon with two graduated surfaces, means projecting from said frame substantially midway between said graduated surfaces on whlch a holder for a pair of tone tools 1s adapted to be removably secured, means on sa1d frame for engaging ano holding the ends of sa1d tool holder in posltion, and means for Vertically adjusting said plate in order to bring it substantially in the same plane as the surfacing portions of the tools.

6. A protractor for the mounting of toric tools in tool holders, including a frame, a scale plate with two semi-circular recesses therein graduated from zero to 180 degrees,

means for adjustably'moun-ting said plate inconnection with said frame, means projecting from the frame opposite a point between said semi-circular recesses for se curing a toric tool holder midway its ends, and adapted to carry a toric tool on each end and means on the frame opposite each graduated recess for engaging and holding the ends of the tool holder so that the tools will beheld in said graduated recesses.

In witness whereof, I have hereunto affixed my signature.

QHN HARVEY PEARSON. 

